I've had the back tires on my truck for 20,000 miles. I have tons and tons of tread on the sides of my tire, but there is a lot of wear in the middle. I've ran them at 55 psi the whole time. The truck specifies 60 psi for a load range D tire. My load range E tires specify 80psi. So is 55 psi too much for load range E tires on a 4500 pound truck? I dropped it down to 40 for now, and I guess I'll see how that goes.

 

Two things cause middle tread wear. Too much pressure and/or too narrow of a rim.

 

Ok. Factory size is 7.5 x 16. I'm running 235/85/16. From a size conversion calculator i found, 7.5 x 16 works out to a 191/104/16 in metric. So the 235/85/16 is much wider, but it is listed as the stock tire size for the 7500lb gvw package on most websites. And a 235 width tire is, in general, fine for a 6 inch rim, right?

 

235-75-15 was the most popular size of light truck tire for many years. That's what I have on mine with stock 15" wheels.

 

235s are fine on a 7.5 inch rim so the only answer left is too much pressure or faulty tires which I would doubt.

 

i also agree that there was too much air pressure in your tires. you only need to fill your tires up to as high as they say on the tire if you are hauling a heavy load.

 

Ok. I'll try 40 for now. I think my stock rims are 6 inch though, not 7.5. The pressure is specified for 7.5x16 on 16x6 on the door jamb.

 

6 inch rims are the smallest recommended rim for those tires but still OK. Any time you change the tires from stock you can no longer use any of the info from the trucks placards. Always use the info on the tire itself. The changes in tires over the years has been so tremendous that I would not trust any info that was published when our trucks were made.